I Have Been Feverish For 36 Hours, Had Incredibly Bad

I have been feverish for 36 hours, had incredibly bad acid reflux, nausea & headpain. I took some pain relief, some Gaviscon & a Nexium control tablet this morning. I have just produced a very black loose stool, and feel very sick. I am worried. Should I contact my doctor in morning?
I am female aged 40, do not have periods or take iron tablets. Neither have I eaten any dark food. I have had no food since lastnight.